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Data Profile: National Emission Trends (NET)
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National Emission Trends (NET)
The National Emission Trends (NET) database is available from the U.S. Environmental Protection Agency (EPA). The NET database is an emission inventory that contains data on stationary and mobile sources that emit criteria air pollutants and their precursors. The database also includes estimates of annual emissions of these pollutants from point, area, and mobile sources. An emission inventory lists by source, emissions of air pollutants in a specific area for a specific time.

Four of the six criteria pollutants are included in the NET database: carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2) and particulate matter (PM10 and PM2.5). The NET also includes emissions of volatile organic compounds (VOCs), which are ozone precursors, and ammonia (NH3).

The main sources of data for the NET are:
  • For electric generating units, EPA's Emission Tracking System/ Continuous Emissions Monitoring Data (ETS/CEM) and Department of Energy fuel use data.
  • For other large stationary sources, state data and older inventories where no state data was submitted.
  • For on-road mobile sources, the Federal Highway Administration's (FHWA's) estimate of vehicle miles traveled and emission factors from EPA's MOBILE Model.
  • For non-road mobile sources, EPA's NONROAD Model.
  • For stationary area sources, state data, EPA-developed estimates for some sources, and older inventories where no state or EPA data was submitted.

State and local environmental agencies supply most of the point source data. EPA's supplies emissions data for electric power plants
The NET includes emission estimates for all 50 States, the District of Columbia, Puerto Rico, and the Virgin Islands.
First Year1996
Last Year1999
FrequencyEvery three years.
  • EPA calculates county aggregate emissions for each year between the inventory releases, based on economic growth activity. Aggregate emissions data currently is available for the years 1985 through 1999, and emissions data for individual point sources (facilities) is available for years 1996 and 1999.
   Summary Tables
   National Transportation Statistics
Air Pollution Trends in Selected Metropolitan Statistical Areas
Areas in Nonattainment of National Ambient Air Quality Standards for Criteria Pollutants
Estimated National Emissions of Carbon Monoxide
Estimated National Emissions of Lead
Estimated National Emissions of Nitrogen Oxides
Estimated National Emissions of Particulate Matter (PM-10)
Estimated National Emissions of Particulate Matter (PM-2.5)
Estimated National Emissions of Sulfur Dioxide
Estimated National Emissions of Volatile Organic Compounds
U.S. Carbon Dioxide Emissions from Energy Use by Sector, 1990-1998
   Related Links
EPA's Links Page
   Data Source and Contacts
Data Provider AgencyU.S. Environmental Protection Agency
Data Provider OfficeAIRData
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